The Arsenal legend believes the Gunners need to develop a ruthless streak that has become synonymous with Chelsea FC

Per Mertesacker has challenged Arsenal to develop Chelsea FC’s “ruthless streak” to ensure a successful spell under Unai Emery.

The Spanish head coach took over the reins from Arsene Wenger in the summer after the 68-year-old led the Gunners to a disappointing sixth-placed finish in his 22nd season in charge.

Emery has wasted no time overhauling the north London side’s squad with five summer signings and an adjustment of Arsenal’s tactics with an emphasis on ball retention.

Arsenal lost 2-0 to defending Premier League champions Manchester City in their season opener at The Emirates before a 3-2 defeat by Chelsea FC in west London to suggest Emery’s methods would require time.

However, the Gunners have responded with six successive Premier League victories to hoist themselves up to fourth place in the Premier League table ahead of Tottenham Hotspur and Manchester United.

While Arsenal haven’t beaten any teams of real calibre during that run, Emery’s side can take confidence from their improved attacking displays following a 5-1 rout of Fulham last time out.

Chelsea FC have won two Premier League titles, the FA Cup and the League Cup over the past five seasons despite having four different managers.

Arsenal’s number one Petr Cech was part of the Chelsea FC team that dominated English football between 2004 and 2014 alongside Manchester United.

World Cup winner Mertesacker, who is the manager of the club’s academy, identified one area where Arsenal need follow Chelsea FC’s example to improve under Emery if the Spanish head coach is to be a success at The Emirates.

“His [Cech’s] background at Chelsea, that is the way he won,” Mertesacker is quoted as saying by Metro.

“You can feel when we went there it was always tough and we struggled to deal with the intensity and that defensive ruthlessness.

“We can take that on. We have to learn and adapt to what Chelsea have brought.”

Of the new arrivals, Torreira has been the biggest hit at the north London side thanks to his tenacious performances in the middle of the park and his ability to improve Granit Xhaka’s display alongside the summer signing.

Arsenal will welcome Leicester City to The Emirates on Monday 22 October.